Cornea Transplantation Provides Sight To The Eyes
The cornea transplantation, known as “eye transplant” among the public, provides hope for eyesight. Corneal transplantation which is an effective method applied in the treatment of diseases affecting the corneal layer of the eye, rescues the people foggy vision and provides sight to the eyes. Head of the Memorial Şisli Hospital Eye Center Assoc. Prof. Barış Sonmez, MD provides information about cornea transplantation.
If the vision is diminishing and you are not seeing any benefit from glasses
The surgery where the cornea layer, the outermost layer of the eye, is changed is called corneal transplantation or keratoplasty. Corneal tissues used for this operation are obtained from authorized domestic and foreign eye banks. Diseased or damaged corneal tissue may become cloudy, edematous (or swollen) or thin out and lose its proper structure. This affects the light passing through the cornea layer and results in a fuzzy, foggy eyesight. Blurring or thinning in the cornea reduces visual acuity and corneal transplantation is performed if this reduction affects the quality of life of the patient.
Eye rubbing is very harmful
Keratoconus is the most important disease where the cornea becomes thin and astigmatism advances which in turn causes structural deterioration. The collagen fibers in the cornea are normally tightly linked. However the bonds between these fibers become weaker due to genetic predisposition or rubbing the eye too often, the cornea is pulled forward because of this and mildly downward due to gravity as well. In such cases, advancing myopia and astigmatism that is not correctable with glasses develops. For such cases, it is necessary to put forward several treatments to stop thinning out in forward direction. Crosslink is a treatment that is performed to make the cornea tighter. There may be cases where this does not work, or there may be cases where the treatment is performed to late. In this environment, the cornea loses its anatomical integrity and it may be necessary to change the cornea after advanced myopia or astigmatism development.
Diseases which require corneal transplant
Cornea transplantations are not performed for every ocular disease. The diseases in which corneal transplantation is performed include:
- Corneal edema after failed cataract surgery
- Diseases such as keratoconus, cornea thinning and surface map impairment
- Genetic corneal diseases – corneal dystrophies
- Infections, especially corneal staining after ocular herpes and contact lens keratitis
- Damage following accident – trauma to the cornea
- Previous rejection of corneal tissue
Corneal Transplantation via Laser
In corneal surgeries, both the recipient and the donor corneas are prepared via specially designed devices. The instruments and blades used in transplant operations provide millimetric incisions for the operation. Thanks to laser technology, it is possible to perform corneal transplant operation completely without knife. Thanks to the femtosecond lasers, both the recipient cornea and the donor cornea can be prepared with finer incisions to be more compatible with each other.
In most diseases that require corneal transplantation, only a certain layer of the cornea becomes damaged. In this case, only the damaged inner cell layer is replaced. The endothelial cell layer is the innermost layer of the cornea. The most important task of these cells is to keep the cornea transparent for a clear view. Corneal edema develops in some genetic diseases and following eye surgery (cataract surgery – glaucoma surgery) where endothelial cells are damaged. In those cases where the other layers of the cornea are intact, the corneal tissue obtained from the donor is manually divided into layers using devices called microkeratomes or femtosecond lasers. The damaged endothelial layer is removed and the endothelial membrane layer obtained from the donor is inserted into the eye through a 3.5 mm cut. This operation can be performed under local or general anesthesia. Seamless corneal transplant surgery is called endothelial keratoplasty, DSEK and DMEK.
Reducing rejection in seamless corneal transplantation
The advantages of seamless corneal transplantation may be described as below:
- Only the damaged layer of the cornea is changed, reducing the rejection reaction
- The operation is through a smaller cut
- The risk of damage to the intraocular tissues is less than in full-thickness corneal transplantation
- Suture related astigmatism is not possible, the sight normalizes earlier.
- Patients obtain a good vision within approximately one week.
- Since the eye is not completely opened up, it remains more resistant against trauma.
The net result will be determined within 6 to 12 months
The cornea transplantation is performed via a surgical microscope and under sterile conditions. Except for corneal tissue, the equipment and technology used in the surgery differ according to the technique of transplantation. After removal of damaged or blurred corneal tissue in full-thickness corneal transplants, the donor corneal tissue is fixed with stitches. These seams are removed one by one six months after the surgery, depending on the healing progress. Despite better vision in comparison to the past immediately after the surgery, the best vision is obtained after 6 months 1 year, when the astigmatism causing stitches are removed and appropriate glasses or contact lenses are prescribed. In seamless corneal transplantations in the other hand, the donor corneal tissue is manually placed on the inner surface of the eye after it has been prepared manually or with the aid of special devices called microkeratome. A small air bubble is injected into the eye at in order to fixate the graft. Patients use eye drops for a period of time to prevent infection and rejection after corneal transplant surgery.
Return to normal life within one week at the latest
Following surgery, your daily life is not affected in anyway, except avoidance of heavy exercise and trauma to the eye. After surgery, patients return to normal life within one week at the latest. The follow-up examinations are usually performed on the 1st day, 1st week, 1st month, 3rd month and then every 6 months after the surgery. If necessary, the patient is prescribed eyeglasses and contact lenses after all the procedures.